One leader was Benjamin Lett. By his side stood Samuel Peters Hart. Formerly a pro-reform publisher of material highly critical of the Family Compact, Hart's story echoed the tales of many Upper Canada dissidents. He fled to America after a Tory mob wrecked his printing office and dragged him through the snow. That episode warped Hart into a dangerous and vengeful man.
On the morning of July 28, the Guernsey anchored on the north side of Lake Ontario three miles from the quiet town of Cobourg. Hart, Lett and four others—Miles Luke, William Baker, William Watkins, Henry Wilson—disembarked. They carried a trunk loaded with armaments and combustible materials—the tools for murder and arson. They journeyed to a farm owned by a fellow Hunter and his son near Cobourg. There Henry Moon, a local Hunter, joined them.
Lett and his gang discussed a list of victims—including Sheppard McCormick, a veteran of the Caroline attack—they intended to rob, murder or abduct. They delayed for a day, waiting for repairs to their wagon. In that time, Moon had a change of heart. Though he supported Hunter and Patriot goals, he decided he couldn't be an accomplice to cold-blooded murder. He slipped away and informed Cobourg authorities.
Moon told everything he knew, and it was far more than just this raid by Lett and Hart. He said a network of Hunter cells in Canada, with a stock of arms from America, would soon rise up, commandeer all British steamboats on Lake Ontario and attack Upper Canada from within and without. The mastermind, according to Moon, was Bill Johnston.
Aside: Moon's description sounds like a plan Johnston and General Donald McLeod might have dreamed up. The scale was grand and the tactics clever. At this time, Johnston lurked once again in the Thousand Islands, acquiring boats and recruiting crews. Of course, Moon may have invented the story.
In Cobourg, a militia captain hastily assembled a band of armed men and hurried to the farmhouse where Hart's gang reposed. Bursting in, they captured everyone but Lett and Luke: they escape out of a first storey window and vanished in the night.
On September 13, 1839, the Cobourg conspirators were tried before Judge Jonas Jones and found guilty. The judge handed down jail terms between six months and seven years (for Hart). Moon, the prosecution's star witness, and his family disappeared; fleeing for safety after Moon's treachery to the Hunters.
Lett Strikes AgainThe same day that Judge Jones sentenced the Cobourg conspirators, someone crossed the Niagara River from New York State and burned a church in Chippawa within eyesight of the dwelling of John Ussher, brother of Edgeworth Ussher murdered by Lett. Several days later, arson claimed nearby buildings owned by a prominent loyalist. While no proof existed, locals blamed Lett. He never denied it.
Lett didn't stop there.